Cancer

Depending upon their tissue of origin, cancers are classified as follows:

• Carcinomas: Carcinomas refers to the cancers of epithelial tissue origin. The epithelial tissue is the covering of any organ that faces the external or internal environment, such as the skin, gut lining, oral lining or the lining of the nose. They are the most commonly reported types. Some examples of carcinomas include prostate cancer, breast cancer and squamous cell carcinoma of the skin.
• Sarcomas: These are the malignancies of connective tissue origin. The connective tissue supports and connects different parts of the body. For example, cancer of the adipose tissue, areolar tissue, tendons, ligaments and bones among others.
• Leukaemia: Leukaemia is the cancer of the blood occurring as a result of uncontrolled growth of the white blood cells. The four main types of leukaemia are lymphocytic (acute and chronic) and myeloid (acute and chronic). The terms lymphocytic and myeloid leukaemia refers to the cancer of cells that are at different stages of maturation to form white blood cells in the bone marrow.
• Lymphomas: These are cancers of the lymph nodes and lymphatic organs. Lymph refers to the fluid that is formed within the interstitial spaces. It has its separate network of lymph vessels and tiny clusters of lymph nodes in multiple regions of the body. Lymph contains lymphocytes, which help fight infections. Cancer of these regions or lymphomas are of two types – Hodgkin’s and non-Hodgkin’s lymphomas.

Furthermore, depending on the organ or the part of body involved, cancer can be classified as follows:

• Breast cancer
• Cervical cancer
• Oral cancer
• Prostate cancer
• Uterine cancer
• Ovarian cancer
• Blood cancer
• Lung cancer
• Stomach cancer
• Bone cancer
• Colorectal cancer
• Throat cancer
• Liver cancer
• Skin cancer
• Bladder cancer
• Brain cancer
• Kidney cancer
• Testicular cancer
• Pancreatic cancer
• Endometrial cancer
• Vaginal cancer

The stages of cancer can be determined by the assessment of the cancerous tissue. ‘Grading’ and ‘staging’ are two methods to predict tumour behaviour and assist in the treatment plan after a malignant tumour has been detected. Grading is histologic, that is the tissues are studied under a microscope, whereas staging is clinical, and is detected by a general examination.

Grading

After examining the tissue under a microscope, cancer is categorised into grades. The microscopic picture of cancerous tissue gives information about two things: the rate of cancerous growth and the structure of the cancerous cells (degree of anaplasia) as compared to the healthy cells. A cancer is termed as benign when there is a significant amount of cell growth seen in a particular area. When the cancer cells are spread across and not located in a particular area, it is termed as metastatic. The Broder’s grading system grades cancer cells based on the extent of differentiation of the cells, which ranges from most differentiated, which refers to the cells that look normal and spread slowly to the most undifferentiated cells, which are the cells that look quite different from how they originally appeared. These grades are:

• Grade I: Well differentiated
• Grade II: Moderately differentiated
• Grade III: Moderately differentiated
• Grade IV: Poorly differentiated

A pathological examination, lab tests as well as a clinical examination of the sample containing the cancer tissue, are performed to determine the extent to which the tumour has spread.

To determine the stage and grade of cancer, the TNM staging and the American Joint Committee (AJC) staging are the two most important and currently used staging methods.

Staging

TNM staging: The TNM has 3 components, where T refers to the primary tumour, N stands for regional lymph node involvement and M is for distant metastases. The three components have numbers denoted to indicate the extent of involvement, as follows:

• T0 - No tumour detected 
• T1-3 - Numbers 1 to 3 indicate the size of the tumour in an ascending order, which implies that greater the number, greater is the size of the tumour and its spread to nearby structures. 
• N0 - Lymph nodes not involved.
• N1 to N3 - These denote the extent of lymph node involvement with respect to the size, location and number of lymph nodes involved. Again, higher the number, greater are the number of lymph nodes involved.
• M0 - Absence of metastasis spread to other sites.
• M1- Spread of tumour to other sites is present.

Based on the part affected, the symptoms of cancer vary vastly. Some typical signs and symptoms that may be experienced irrespective of the type and site of cancer are:

• Abnormal loss or gain of weight
• Weakness and fatigue
• Frequent bruising of the skin
• The feeling of a lump beneath the skin
• Breathing problems and coughing longer than a month
• Skin changes, such as changes in the size and shape of the existing moles or appearance of lesions
• Easy bruising of the skin
• Digestive issues like diarrhoea or constipation
• Difficulty swallowing
• Loss of appetite 
• Changes in voice quality
• Persistent episodes of fever or night sweats
• Muscle or joint pains and delayed wound healing
• Recurrent infections

If you notice any of these symptoms, it is imperative to talk to your doctor as it is best to manage cancers at the earliest. You must also note that all of these symptoms are not observed in all and not everyone experiences them intensely until at a later stage. In fact, some may notice no symptoms at all, unless cancer is flukily detected upon a general examination. So, it is important that you do not ignore even the mildest of the symptoms.

Causes

Cancer occurs as a result of certain changes or mutations in the DNA of cells. DNA, which is considered to be the brain of the cell gives instructions regarding cell growth and multiplication. Errors in these instructions can lead to uncontrolled growth and multiplication causing cancer. 

Substances that may lead to cancer development are termed as carcinogens, which are the primary causes of cancer along with other risk factors. They can be chemical, for example, substances found in tobacco smoke; physical, such as ultraviolet radiation; or biological, such as the Human Papillomavirus. A single carcinogen cannot be held responsible for causing cancer. Multiple carcinogens along with other factors, such as health and diet, lead to the manifestation of cancer in an individual.

Risk Factors

The most common risk factors of cancer are:

• Dependence on tobacco and tobacco-related products in the form of smoking or chewing causes lung and mouth cancers.
• Increased alcohol consumption is known to increase the risk of liver cancer among many others.
• Unhealthy diet and eating refined foods that are low in fibre are known to cause colon cancer.
• Hormones, such as raised levels of testosterone and oestrogen are risk factors for the development of prostate cancer and breast cancer respectively.
• Advancing age increases the likelihood of developing certain cancers like colon cancer, breast cancer, prostate cancer and many others.
• Genetic defects or mutations increase the likelihood of cancer tremendously e.g., women with mutations in the BRCA1 and BRCA2 genes are prone to developing breast cancer.
• Positive family history increases the risk of certain types of cancer like that of the breast.
• Occupational hazards like exposure to dyes, tar, and chemicals like aniline, increases the risk of certain cancers like bladder cancer.
• Bacterial and viral infections cause systemic disorders, which act as a predisposing factor for cancer, for example, H. pylori infection can lead to the development of stomach cancer; hepatitis B and C infections may lead to liver cancer and Human Papillomavirus infection leading to cervical cancer.
• Overexposure to radiations from repeated X-rays or sunlight which contains harmful ultraviolet rays also increases the risk of developing cancer.
• Obesity, high intake of fat and limited physical activity are significant risk factor for the occurrence of several types of cancer in both men and women.
• Stress is determined to be a leading risk factor for cancer because of its far-reaching effects. In addition, weakened immunity due to past or present medical conditions increases a person’s susceptibility to cancers.

As you may note, most of these risk factors, other than the ones, which are genetic or age-dependent can be averted with a healthier lifestyle and adequate protection from infections and pollutants. If you have a positive family history or are generally at a higher risk of any type of cancer, it is essential that you make the desired lifestyle changes to reduce your risk.

It is possible to prevent most types of cancers by adopting a healthier lifestyle and managing the risk factors. Here is what you can do for the best:

• Avoid smoking. (Read more: Benefits of quitting smoking)
• Limit alcohol consumption.
• Avoid overexposure to sunlight.
• Have a diet rich in fiber. Avoid excessive consumption of fats in your diet and stay away from red meat sources like pork and beef. Also, limit the intake of processed foods in your diet.
• Limit exposure to radiations by wearing protective gear in case of occupational exposure.
• Exercise regularly and maintain a healthy weight and BMI.
• Consume a healthy, balanced diet.
• Go for regular checkups and screenings to rule out the presence of abnormalities or to identify the disease in its early stages.
• Consult a doctor in case of a longstanding problem or non-healing injury or excessive bruising of the skin.
• Go for regular immunisations. The Human Papillomavirus (HPV) vaccine helps prevent cervical cancer and is a must. Another vaccine to consider is the hepatitis B vaccine, which prevents infection the with hepatitis B virus, which is a known risk factor for liver cancer.
• Identify ways to cope with stress. Spend time with family and friends, pursue a hobby, do yoga or meditation, follow a sport, or do other things that help you calm your mind.

When choosing a diagnostic test, the doctor will consider the person’s age, medical history, gender, family history, type of cancer suspected, the severity of symptoms experienced and any previous test results. Following are the most common diagnostic tools that are used to determine the probability of a cancer:

• Physical examination to look for any abnormalities.
• Laboratory assessment of the person’s blood sample (complete blood count, ESR test, C- reactive protein test, liver function test and kidney function test and more).
• Specific tests like cancer antigen 19.9 (CA 19.9), carcinoembryonic antigen (CEA) or prostate-specific antigen (PSA) might be advised by the doctor when suspecting cancer of a specific origin.
• Imaging techniques like X-ray, CT scans, MRI, barium meal study, bone density scan, PET scan, SPECT scan, USG etc may also be advised. Biopsy of the tissue collected from the suspected tumour will be examined under a microscope to identify the stage of tumour, the severity of its multiplication and type of cells of the tumour. 

Treatment options of cancer are primarily of two types:

Surgical methods

It involves the removal of the abnormal growth or mass of cells, which is followed by biopsy of the excised part. This is particularly helpful when the tumour is accessible and localised.

Non-surgical methods

It involves chemotherapy, which basically consists of medications to destroy the abnormally growing mass of cells and radiotherapy, which uses radiations like gamma rays directed at the growing tumour.

Sometimes, both surgical and non-surgical methods are used. First, radiotherapy or chemotherapy is advised to reduce the size of the tumour and then excision of the cancerous lesion is performed. After the surgery, chemotherapy or radiotherapy is again performed in the area to avoid further spread of the lesion to other sites.

Other treatment options are hormonal therapy, immunological treatments, bisphosphonates etc. These are used as per need for specific cancers. E.g. Breast and prostate cancer are amenable to treatment with hormonal therapy.

Medications are also prescribed to manage the associated symptoms of cancer. These may include painkillers, antacids, antipyretics to manage individual symptoms.

Often, palliative care is the only treatment possible, where patches of morphine or other painkillers are used to alleviate the continuous pain and discomfort due to cancer, as cancer itself cannot be controlled due to its widespread nature. 

Novel treatments

The field of cancer therapeutics is every emerging. New treatment methods are being introduced almost every year to reduce cost and prevent the recurrence of cancer. Depending on its type, the recurrence rate of cancer ranges from about seven to almost 100 percent. The latest research is focussing on finding ways to understand the working of cancer cells so as to find the best possible ways to inhibit their growth and spread. This includes the studies on cancer stem cells for identification of CSC markers and development of specific T cells to target and kill CSCs to finding out the specific DNA mutations and genetics behind the development of cancer.

Prognosis

The outcome of cancer depends on its type. Small sized cancers or those in the initial stages are easy to treat and hence have an excellent prognosis. On the other hand, the outcome is poor for metastatic lesions, as the spread cannot be completely arrested and may lead to multiple system failures or other complications. Other than this, the prognosis also depends on the type of the tumour cells and the area of the body affected. 

Complications

The severity of complications also depends on the part of the body affected. Metastatic tumours pose a far greater threat than those which do not spread. The complications, depending on the organ systems affected, include:

• Heart failure
• Pulmonary oedema (retention of fluid in the lungs)
• Liver failure
• Kidney failure
• Repeated infections due to poor immunity

Cancer refers to the uninhibited growth of cells, which grows independently and is arranged atypically without serving any functions. Random DNA mutations are believed to be the cause of most types of cancer.

However, not all types of cells in a tumour are the same. A tiny portion- about 1%- comprises cancer stem cells (CSC). CSCs are very much like the normal stem cells of the human body in that these are pluripotent and have the capacity of self-renewal. It is these cells that help cancer spread in the body and make new tumour cells by dividing and differentiating. 

As per the reports published by WHO, cancer is the second largest cause of mortality in the world.

Simple lifestyle changes can be adopted by affected individuals in order to improve their quality of life and to manage symptoms. These may include:

• Eat healthy home-cooked meals, which are rich in all nutritious components.
• Exercise regularly. 30 minutes of moderately vigorous exercise for 5 days a week may help. If you are unable to perform intense physical activities, 30 minutes of brisk walking may help.
• Avoid tobacco and alcohol consumption.
• Go for regular health checkups to assess your progressive.
• Manage stress better by doing yoga, meditation or following a passion or hobby.
• Stay happy, cheerful and positive at all times. Not all cancers are incurable and deathly.